Noun: a dirty scumbag; usually used to describe an individual who has seriously fucked you over. More specifically, it is more of a ramming-your-pants-down-to-your-ankles followed by a repeated anal-insertion-with-no-lube kind of fuck-over. (It's pretty bad.)
Example 1: "What a prick fuck!"
Example 2: "You prick fuck!"
Example 3: "Hey, you're a prick fuck, you asshole!"